Method and System for Synthesizing a Lane Image

Abstract

A method for synthesizing a lane image is proposed in the present application. This method includes the following steps. M continuous image frames are retrieved at a frame rate f from a video image capture device. A quantity N for image mapping is determined based on a dash length L of a dashed line and a distance S between two dashes of the dashed lines. A frame interval for mapping image frames is determined based on the dash length L, the distance S, the velocity v, and the frame rate f. At least N image frames are retrieved from the M continuous image frames at the frame interval. The at least N image frames are synthesized to obtain the lane image using an image synthesizing device.

What is claimed is: 
     
         1 . A method for synthesizing a lane image, comprising:
 retrieving M continuous image frames at a frame rate f from a video image capture device;   determining a quantity N for image mapping based on a dash length L of a dashed line and a distance S between two dashes of the dashed lines;   determining a frame interval for mapping image frames based on the dash length L, the distance S, the velocity v, and the frame rate f;   fetching at least N image frames from the M continuous image frames at the frame interval; and   synthesizing the at least N image frames to obtain the lane image by an image synthesizing device.   
     
     
         2 . The method as claimed in  claim 1 , wherein N=ceil(S/L)+1. 
     
     
         3 . The method as claimed in  claim 1 , wherein the frame interval has a value ranged between ceil((f/v)(S/(N−1))) and floor((f/v)L). 
     
     
         4 . The method as claimed in  claim 1 , wherein the step of synthesizing the at least N image frames to obtain the lane image includes: using an image addition algorithm to form the lane image. 
     
     
         5 . The method as claimed in  claim 1 , wherein the M continuous image frames are configured to be saved in a memory buffer built in an embedded system. 
     
     
         6 . The method as claimed in  claim 1 , wherein each of the M continuous image frames has an image being selected from one of the group consisting of a binary image, a gray scale image and a color image. 
     
     
         7 . The method as claimed in  claim 6 , further comprising a step of:
 taking the union of the at least N image frames to form the lane image.   
     
     
         8 . The method as claimed in  claim 6 , further comprising a step of:
 processing each of the at least N image frames with a max filter to form the lane image.   
     
     
         9 . A method for real-time image synthesis from a video image capture device built on a vehicle, comprising:
 retrieving M continuous image frames at a frame rate f from the video image capture device built on the vehicle;   determining a frame interval for mapping image frames based on a dash length L of a dashed line, a distance S between two dashes of the dashed lines, a real-time velocity v of the vehicle and the frame rate f,   determining a quantity N for image mapping at least based on the dash length L and the distance S;   fetching at least N image frames from the M continuous image frames at the frame interval; and   synthesizing the at least N image frames to obtain a lane image by an image synthesizing device.   
     
     
         10 . The method as claimed in  claim 9 , wherein N=ceil(S/L)+1. 
     
     
         11 . The method as claimed in  claim 9 , wherein the frame interval has a value ranged between ceil((f/v)(S/(N−1))) and floor((f/v)L). 
     
     
         12 . The method as claimed in  claim 9 , wherein each of the M continuous image frames has an image being selected from one of the group consisting of a binary image, a gray scale image and a color image. 
     
     
         13 . The method as claimed in  claim 12 , further comprising a step of:
 taking the union of the at least N image frames to form the lane image.   
     
     
         14 . The method as claimed in  claim 12 , further comprising a step of:
 processing each of the at least N image frames with a max filter to form the lane image.   
     
     
         15 . A lane image synthesizing system of a vehicle, comprising:
 a database containing a plurality of images; and   an image mapping module configured to:
 determine a quantity N for image mapping; 
 determine an interval based on parameters including at least one of a velocity of the vehicle and a sampling rate of the plurality of images; 
 fetch at least N images from the plurality of images according to the interval; and 
 synthesize the at least N images into a lane image. 
   
     
     
         16 . The lane image synthesizing system as claimed in  claim 15 , wherein the images are stored in frames. 
     
     
         17 . The lane image synthesizing system as claimed in  claim 15 , wherein the parameters include a length of a dashed line and a distance between two dashes of the dashed lines. 
     
     
         18 . The lane image synthesizing system as claimed in  claim 15 , further comprising an image processing module configured to take a procedure selected from a group consisting of regions of interest cropping and scaling, a contrast enhancement, an edge extraction, a noise reduction and a combination thereof for producing the lane image. 
     
     
         19 . The lane image synthesizing system as claimed in  claim 18 , further comprising a prompting module configured to proceed:
 a line detection to generate a set of candidate lines;   a lane determinant based on a characteristic of each of the candidate lines to identify two lane lines of the lane;   a lane departure detection based on a reference line of the vehicle and the two lane lines; and   popping up a warning message when the vehicle deviates from one of the reference line and the lane.   
     
     
         20 . The lane image synthesizing system as claimed in  claim 19 , wherein the reference line is a side of a central area of the lane in which the center line of the vehicle is located.